But vague language in this part of the law — which was passed three years ago this Saturday — has led to a slew of quirks and questions.

Staffers who work in lawmakers’ personal offices go into exchanges — but those who work for committees don’t. And the lawmakers themselves get Obamacare — unless they are among the roughly 40 senators and 115 House members on Medicare.

And there’s a big thorny unresolved question about money: whether members and staffers in exchanges will still get a significant part of their health insurance premiums subsidized by their employer, just like other government workers. If they lose that subsidy, it’s like getting a pay cut of several thousand dollars.

“The sad thing is, too many Americans will be dealing with this in 2014 — not just Hill staffers,” said Courtney Austin Lawrence, legislative director for Rep. Bill Cassidy (R-La.). “My general concern with the exchange and Obamacare goes far beyond my own individual coverage. I think it’s a bad policy for taxpayers, patients and physicians.”

Ambiguities in the wording of the law also raise questions about whether long-promised retirement health plans could disappear for Hill staff. Those valuable benefits available after 20 years of service had been tied to participation in the Federal Employees Health Benefits program, but the exchanges aren’t part of FEHB.

Grassley says it’s up to the Obama administration to make it all work out.

“The administration continues to reassure Congress and the American people that the implementation of the president’s health care law is under control,” he said. “So the onus is on the administration to answer all implementation questions and to avoid unintended consequences.”

Several offices on Capitol Hill are quietly lobbying the Office of Personnel Management, which has to make decisions on the subsidy and retirement questions. Rules are expected to be released as soon as May, and exchange enrollment is supposed to start in October.

Democrats are hoping for a broad interpretation to allow the federal government to keep contributing to employees’ premiums, even though they won’t be in FEHB anymore, according to sources familiar with the conversations. They worry that if staffers’ already low pay is cut further, the Hill is going to become a less attractive place to work.

“Many members have concerns about this possible decision by OPM and the potential impact that this could have on the quality of the House workforce,” said Drew Hammill, a spokesman for House Minority Leader Nancy Pelosi (D-Calif.). “We are hopeful this issue can be resolved as soon as possible to avert any impact on staff.”

Today, the federal government pays an average of 70 percent of health care premiums for its employees — including members of Congress and their staffers. That’s pretty typical of a large U.S. employer. And both Democrats who like the law and Republicans who hate it would feel the difference in their pocket if the subsidies vanished.